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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 18 Abstracts search results
Document:
SP143-05
Date:
May 1, 1994
Author(s):
R. A. Cook and F. E. Fagundo
Publication:
Symposium Papers
Volume:
143
Abstract:
A new type of short-span bridge system has been developed and implemented over the Albermarle Sound south of Edenton, North Carolina. The new system incorporates precast flat-slab sections that are post-tensioned for continuity. The new system has the potential to replace traditional trestle-type bridges constructed using simple-span prestressed beams with a cast-in-place deck. A continuous two-span, half-scale model of the bridge system was built and tested under various load conditions. The bridge was evaluated analytically and experimentally for the transfer load case (dead load plus prestress), the maximum negative moment service load case, cracking load, and ultimate load. The model bridge performed as expected for all cases. Comparisons between analytical and physical models showed good correlation for all types of tests. At service load levels, the bridge exhibited a linear elastic response with no evidence of cracking. The ultimate load and deflections of the new bridge system were readily predicted by standard behavioral models for prestressed concrete.
DOI:
10.14359/4600
SP143-08
S. M. Kulkarni and S. P. Shah
Discusses important issues relevant to high-rate closed-loop testing of reinforced concrete beams. To obtain a high rate of loading from a closed-loop machine, special considerations are required in the design as well as operation of the machine. These issues are discussed briefly. Useful insight into behavior of a specimen in a high-rate closed-loop test is provided by some analytical expressions supplied here for single-degree-of-freedom (SDOF) and multiple-degree-of-freedom (MDOF) specimen systems. Advantages of displacement control over load control are apparent from the expressions obtained. Preliminary results of displacement-controlled tests conducted on reinforced concrete beams at low and high rates are reported. The specimen deformation-versus-time curve in these tests indicates that, for this setup, the test machine used in this project can apply an essentially constant velocity. Crack pattern obtained for the beams as well as inspection of load and specimen deformation signals indicate that the manner of loading was quasi-static (that is, free of inertial effects) even for the high-rate case. The load-deflection curve for the high-rate case exhibits a down-sloping portion after a small plateau.
10.14359/4601
SP143-04
B. Massicotte and A. Picard
Describes details of an extensive monitoring program carried out during the strengthening of the Grand Mere Bridge, a cast-in-place post-tensioned segmental box girder structure built in 1977. The testing program comprised various measurements taken before, during, and after the prestressing application. Electrical strain gages, mechanical strain gages, vibrating wire gages, and thermocouples were among the measuring instruments used. A bridge testing data acquisition system in a vehicle and an autonomous data acquisition system were used, together with manual reading devices. The field measurement program was carried out during strengthening. Some instruments used allow the monitoring of the bridge over a long-term period.
10.14359/4608
SP143-01
M. H. Maher, B. Chen, J. D. Prohaska, E. G. Nawy, and E. Snitzer
A novel fiber optic sensor was tested on reinforced concrete beams with the objective of monitoring strain due to flexural deformations. A fiber optic Bragg grating (FOBG) sensor, developed recently at the United Technologies Research Center (UTRC) for monitoring of strain in structural composites, was used. The FOBG sensor was tested in beam models to measure load-induced strain. Results showed that the FOBG sensor can be accurately and effectively used to monitor strain for both existing and new concrete structures. A number of issues, such as sensor bonding to the structural component, sensor placement, and practical instrumentation techniques, were addressed in this study.
10.14359/4579
SP143-02
V. Sharma, W. L. Gamble, J. Choros, and A. J. Reinschmidt
Load tests were conducted on three recently constructed precast pretensioned concrete railroad bridges. The three bridges tested were instrumented at their centerline of span with concrete strain gages applied to appropriate locations to quantify the bridge behavior and to obtain impact factors. A dedicated test train was used to apply the loading for all the measurements. This train consisted of two locomotives followed by 10 freight cars representative of most common types of cars used in modern freight trains. The test trains had a total gross weight of 1250 tons and a length of 1400 ft and included five platform-type intermodal cars, 89-ft flat cars (TOFC/COFC), and also hopper and box cars. The test train was operated at speeds of up to 70 mph. Paper describes the bridges tested, with special emphasis on field testing techniques and the personal computer-based data acquisition system.
10.14359/4580
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